Investigation of water quality in the Great Sand Dunes National Monument and Preserve, Saguache County, Colorado, February 1999 through September 2000: Qualifying for outstanding waters designation

Ferguson, Sheryl

Great Sand Dunes National Monument and Preserve is located on the eastern side of the San Luis Valley in south-central Colorado. The monument covers 60.4 square miles in Saguache and Alamosa Counties and lies at the base of the Sangre de Cristo Mountains, where a unique combination of climate, topography, and hydrology has created and maintained the Nation’s tallest inland sand dunes. Maintaining the high surface-water quality in the Great Sand Dunes National Monument and Preserve is identified as a critical issue by the National Park Service. Additionally, the National Park Service has indicated a desire to pursue an Outstanding Waters Designation, which offers the highest level of water-quality protection available under the Clean Water Act and Colorado regulations. This designation is designed to prevent any degradation from existing conditions. Assessment is needed to evaluate whether the water quality of the streams in the monument meets the requirements for an Outstanding Waters Designation. The U.S. Geological Survey (USGS), in cooperation with the National Park Service, investigated the water quality at 15 sites from February 1999 through September 2000 to identify baseline water-quality conditions and to determine if the water met standards to qualify for the Outstanding Waters Designation. This report describes current water-quality conditions in streams in the monument and compares the water-quality data to Colorado instream standards to assist the State of Colorado Water Quality Control Commission in the determination of qualification for Outstanding Waters Designation.